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Aircraft Certification and Production Standards
From SKYbrary Wiki
Aircraft Certification Requirements
Aircraft certifications requirements are derived from ICAO Annex 8 ‘Airworthiness of Aircraft’ and ICAO Doc. 9760 “Airworthiness Manual” Volume II ‘Design Certification and Continuing Airworthiness”. Each contracting state then establishes its own applicable regulations to implement internationally agreed standards and recommended practices.
Comparison of US and EU Regulations
In the USA and EU, procedures for certification of aeronautical products and the related organisational approvals are published in FAR Part 21 and EC Regulation 1702/2003. In addition to these procedures the requirements/specifications for certification of each category of products are published in different regulations and certification specifications.
The fundamental difference between the USA and EU system in this regard is that Certification Specifications published by EASA are non-binding technical standards. However, compliance with CS is a necessary condition for obtaining the relevant regulatory approval or certification. CS material may therefore be regarded as binding when taken in conjunction with the binding rules which require compliance with the CS. EASA Certification Memoranda provide another perspective on this matter.
The following list shows a list of airworthiness standards (US) and certifications specifications (EU) applicable to different categories of aircraft.
|Electronic Code of Federal Regulations||EASA Certification Specification|
|FAR Part||Title||EASA CS||Title|
|CS-22||Sailplanes and Powered Sailplanes|
|23||AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES||CS-23||Normal, Utility, Aerobatic and Commuter Aeroplanes|
|25||AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES||CS-25||Large Aeroplanes|
|27||AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT||CS-27||Small Rotorcraft|
|29||AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT||CS-29||Large Rotorcraft|
|31||AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS||CS-31GB CS-31HB||(Gas Balloons) (Hot Air Balloons)|
|33||AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES||CS-E||Engines|
|35||AIRWORTHINESS STANDARDS: PROPELLERS||CS-P||Propellers|
|CS-LSA||Light Sport Aeroplanes|
|CS-VLA||Very Light Aeroplanes|
|CS-VLR||Very Light Rotorcraft|
Acceptable Level of Safety
As part of the type certifications process for particularly transport category aeroplanes, manufacturers need to demonstrate how they meet the acceptable level of safety defined in Part 25 and CS 25. Such specifications also makes reference to ARP4761 "Guidelines & Methods for Conducting Safety Assessment Process on Civil Airborne Systems and Equipment", which details the methodologies to be used such as:
- Functional Hazard Assessment,
- Fault Tree Analysis,
- Failures Modes and Effects Analysis,
- Common Cause Analysis,
- Zonal Safety Analysis,
- Particular Risk Analysis and
- Common Mode Analysis.
Unfortunately there are number of accidents that could have been prevented by the effective use of these methodologies.
Quality Management System
In addition to the robust design processes and the compliance with the regulations to demonstrate acceptable level of safety, the TC holder must have effective quality management systems in place particularly in order to ensure that the parts received from supply chain meets the required standards. For this reason International Aerospace Quality Group has created the AS/EN 9100 family ‘Quality Management System Standards for Aerospace Industry’. Since their introduction in 1999, they have been continually developed and currently specific standards are published for manufacturing organisations (AS/EN9101), maintenance organisations (AS/EN 9111), part suppliers (AS/EN9121) etc.
Accidents and Incidents
The following events for which reports held on SKYbrary cite an OEM design fault as a contributory factor:
- B733, vicinity Bournemouth UK, 2007 (LOC AW HF) (On 23 September 2007, a Boeing 737-300 operated by Thomsonfly, on routine ILS approach at night to Bournemouth Airport, experienced a stall during early stage of the approach. The auto-throttle disengaged with the thrust levers in the idle thrust position. The disengagement was neither commanded nor recognised by the crew and the thrust levers remained at idle throughout the approach. As result of the stall, the commander took control and initiated a go-around. During the go-around the aircraft pitched up excessively; flight crew attempts to reduce the aircraft’s pitch were largely ineffective. The aircraft reached a maximum pitch of 44° nose-up and the indicated airspeed reduced to 82 kt. The flight crew, however, were able to recover control of the aircraft and complete a subsequent approach and landing at without further incident.)
- CONC, vicinity Paris Charles de Gaulle France, 2000 (AW FIRE LOC) (On 25th July 2000, an Air France Concorde crashed shortly after take-off from Paris CDG following loss of control after debris from an explosive tyre failure between V1 and VR attributed to runway FOD ruptured a fuel tank and led to a fuel-fed fire which quickly resulted in loss of engine thrust and structural damage which made the aircraft impossible to fly. It was found that nothing the crew failed to do, including rejecting the take off after V1 could have prevented the loss of the aircraft and that they been faced with entirely unforeseen circumstances.)
- A320, Bilbao Spain, 2001 (WX AW) (On 7th February 2001, an Iberia A320 was about to make a night touch down at Bilbao in light winds when it experienced unexpected windshear. The attempt to counter the effect of this by initiation of a go around failed because the automatic activation of AOA protection in accordance with design criteria which opposed the crew pitch input. The aircraft then hit the runway so hard that a go around was no longer possible. Severe airframe structural damage and evacuation injuries to some of the occupants followed. A mandatory modification to the software involved was subsequently introduced.)
- B733, vicinity Pittsburg PA USA, 1994 (AW LOC) (On 8 September 1994, a US Air Boeing 737-300 crashed near Pittsburg USA following loss of control attributed to a rudder malfunction.)
- F70, vicinity Munich Germany, 2004 (AW WX LOC RE) (On 5 January 2004, a Fokker 70, operated by Austrian Airlines, carried out a forced landing in a field 2.5 nm short of Munich Runway 26L following loss of thrust from both engines due to icing.)
- … further results